We have Panasonic cameras that detect motion and send mails and pictures. These are accessible via smartphone or any browser and tilt / pan so we can look all around the house. Those run on the home landline network. No operations cost.
Backed up with a traditional security system that has a monitoring service. Monitors opening, motion, fire, etc. This uses a cellular data connection and has battery power so power outages or losing the utility cables does not compromise protection. There is a monthly fee for monitoring.